This is the 30th year Comfort Dental has offered the free services, and if the event is anything like last year, there will be lines.

More than 100 clinics in 11 states will open their doors to patients at 7:30 a.m. on Wednesday, Dec. 24. There are no qualifications or restrictions, and there's no catch. The free dental care is available to anybody.

Comfort Dental calls it Care Day, realizing that this might be some people's only opportunity to get essential dental care from basic cleanings to extractions. More serious issues are handled on a case-by-case basis at the discretion of the dentists.

Patients are treated on a first-come, first-served basis, which is why lines form early -- hours before the clinics open.

"These people care," Christa Mitchell said. She was one of the many who lined up last year, relieved to have somebody ease the pain she had been experiencing.

In addition to the Arizona clinics, offices in Colorado, Indiana, Kentucky, Missouri, New Mexico, Ohio, Texas, Kansas, Nebraska and Washington are also taking part in Care Day. Some 300 dentists and 1,300 staffers donate their time and expertise to make Care Day happen year after year.

Last year, more than 6,000 patients nationwide received about $1.5 million in free dental care.

More people are expected this year.

"Due to the tough economy, we anticipate a record turnout," Dr. Neil Norton, Comfort Dental's vice president said in a news release. "In a typical year on Care Day, nationally we average 4,000 patients, but last year was more than 6,000, and this year may be even bigger. There are a lot of families out there who just can't afford dental care, and this is their only dental visit all year."

Launched in Colorado in 1984, Care Day is designed to improve accessibility to dental care.

"We provide free dental care to help people. If someone has a bad tooth, hopefully we can make them feel better," Comfort Dental president and founder Dr. Rick Kushner said in a news release. "For some people, including kids, Care Day might be the only time they see a dentist all year. We're dentists, so we give away dental services for the holidays. Care Day is our cornerstone."